visual comfort probability
Visual comfort probability (VCP), also known as Guth visual comfort probability, is a metric used to rate lighting scenes.
VCP is defined as the percentage of people that will find a certain scene (viewpoint and direction) comfortable with regard to visual glare.
[https://web.archive.org/web/20090503190442/http://tristate.apogee.net/lite/lviscom.asp Visual Comfort and Productivity], tristate.apogee.net; retrieved February 16, 2014 via Wayback Machine{{cite journal
|author=Ward, G.J.
|year=1991
|title=RADIANCE Visual Comfort Calculation
|journal=Rapport Interne, LESO, EPFL
|url=http://floyd.lbl.gov/radiance/refer/Notes/glare.ps}}
It was defined by Sylvester K. Guth in 1963.
{{Cite journal
| volume = 58
| issue = 5
| pages = 351–364
| last = Guth
| first = SK
| title = A method for the evaluation of discomfort glare
| journal = Illuminating Engineering
| date = 1963